1. Field of the Invention
The present invention relates to a roller assembly for a roller guide and, more particularly, to a roller assembly for a fishing rod roller guide with smooth rotation and a prolonged service life.
2. Description of the Related Art
A type of fishing rod includes a plurality of roller guides each having a through-hole for receiving a fishing line, so that the moving direction of the fishing line can be controlled by the roller guides. To improve smooth movement of and to reduce wear to the fishing line, it is known to provide a roller assembly on the roller guide.
FIGS. 4 and 5 show a conventional roller assembly including a roller 1′, two bearings 2′, two side covers 3′, an axle 4′, and grease 5′. The roller 1′ includes an annular recess 11′ for receiving a fishing line or the like. An axial hole 12′ extends from an end through the other end of the roller 1′ and includes two flanges 121′ on an inner periphery thereof and two abutting edges 122′ on two ends thereof. The axial hole 12′ further includes two receiving portions 123′ receiving the bearings 2′. Each bearing 2′ includes an inner ring 21′ and an outer ring 22′ receiving the inner ring 21′. The inner and outer rings 21′ and 22′ are rotatable relative to each other. The outer ring 22′ has a diameter slightly smaller than the receiving portions 123′ and includes a flange 221′ abutting against one of the abutting edges 122′. The side covers 3′ are respectively mounted to two ends of the roller 1′. Each side covers 3′ includes an axial hole 31′. An inner side 32′ of each side cover 31′ includes a bulged portion 33′ aligned with the inner ring 21′ of one of the bearings 2′. Each side cover 3′ includes a flange 34′ on an outer periphery coupled to a frame to which the roller 1′ is mounted. The axle 4′ includes first and second axle rods 41′ and 42′ each having an enlarged end 411′, 412′ having a diameter lager than the axial hole 31′ of each side cover 3′. The first axle rod 41′ includes a screw hole 412′. The second axle rod 42′ includes threading 422′ for coupling with the screw hole 412′. The first axle rod 41′ extends through the second axial holes 31′ of the side covers 3′ and the inner races 21′ of the bearings 2′. The second axle rod 42′ is threadedly coupled in the first axle rod 41′. After assembly, the bulged portions 33′ of the side covers 3′ abut against the inner rings 21′ of the bearings 2′. Furthermore, a spacing a′ is formed between the outer ring 22′ of each bearing 2′ and the inner side 32′ of one of the side covers 3′. The grease 5′ is viscous and immovable and received in the spacings a′, allowing smooth rotation of the bearings 2′ relative to the side covers 3′ and avoiding the bearings 2′ from rusting by preventing ambient moisture from entering the spacings a′. However, although the grease 5′ does not flow, it still leaks out of the spacings a′ under the action of centrifugal force when the roller 1′ rotates at high speed. The sealing function is, thus, lost.
Thus, a need exists for an improved roller assembly for a roller guide to reliably avoid entrance of ambient moisture.